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and us for ever, and excluded the possibility of the remotest sympathy between us and their inhabitants; but due reflection will teach us to feel that all these systems have come into existence by the command of the same Creator, and through the operation of the same laws. If we consider the planets, we shall notice that there is a regular decrease of density and increase of bulk as they are farther from the sun. In respect to density, if we take water as the standard, and count it as one, we shall find that Saturn is 2, or less than half; Jupiter, 12; Mars, 32; Earth, 4; Venus, 511; Mercury, 9; or about the weight of lead. Then the distances are curiouly relative. It has been found that if we place the following line of numbers,

0 3 6 12 24 48 96 192,

and add 4 to each, we shall have a series denoting the respective distances of the planets from the sun. It will stand thus:

4

7

10 16 28 52 100 196 Mercury. Venus. Earth. Mars. Jupiter. Saturn. Uranus. It will be observed, that the first row of figures goes on, from the second on the left hand, in a succession of duplications, or multiplications by two. Surely there is here a most surprising proof of the unity of the solar system. It was remarked, when this curious relation was first detected, that there was a want of a planet corresponding to twenty-eight; the difficulty was afterwards considered in a great measure overcome by the discovery of four small planets, — Ceres, Pallas, Juno, and Vesta, revolving at nearly one mean distance from the sun, between Mars and Jupiter. The distances bear an equally interesting mathematical relation to

the times of the revolution round the sun. It has been found that, in respect to any two planets, the squares of the times of revolution are to each other in the same proportion as the cubes of their mean distances, a most surprising result, for the discovery of which the world was indebted to the illustrious Kepler.

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While we thus observe, with admiring wonder, the unity of the laws which govern the different members of the solar system, we shall find our amazement increased if we extend our view to the starry systems beyond; for we cannot fail to observe that the same principles appear to regulate the movements of those remoter spheres. Nor are these independent of each other the whole are linked inextricably together in their revolutions, though all are so far apart and so nicely balanced, that each may perform its separate and peculiar functions. Yet the laws which cause the rotation of their mighty masses, and still hold them in their orbits, is exactly the same which produces the familiar phenomenon of a small whirlpool, or dimple in the surface of a stream. Such dimples are not always single. Upon the face of a river where there are various contending currents, it may often be observed that two or more dimples are formed near each other, with more or less regularity. These fantastic eddies, which the musing poet will sometimes watch abstractedly for an hour, little thinking of the law which produces and connects them, are an illustration of the wonders of the double and triple stars, or binary and ternary systems, discovered in the heavens.

"We have spoken of the laws which govern the movements of the heavenly bodies, and it may be

matter of interest to inquire what they are. All that can be said in answer is, that we see certain natural events proceeding in an invariable order under certain conditions, and thence infer the existence of `some fundamental arrangement, which, for the bringing about of these events, has a force and certainty of action, similar to, but more precise and unerring than, those arrangements which human society makes for its own benefit and calls laws.

"It is remarkable of physical laws, that we see them operating on every kind of scale as to magnitude with the same regularity and perseverance. The tear that falls from childhood's cheek is globular, through the efficacy of the same law of mutual attraction of particles which made the sun and planets round. The rapidity of Mercury is greater than that of Saturn, for the same reason that when we whirl a ball round by a string, and make the string wind up round our fingers, the ball always flies quicker and quicker as the string is shortened. Two eddies in a stream, as has been stated, fall into a mutual revolution at the distance of a couple of inches through the same cause which makes a pair of suns link in mutual revolution at the distance of millions of miles.

"There is, we might say, a sublime simplicity in this indifference, in these grand regulations, to the vastness or minuteness of their operations. Their being uniform, too, throughout space, as far as we can scan it, and their being so unfailing in their tendency to operate, provided the proper conditions are presented, afford to our minds matter for the gravest consideration.

"Nor should it escape our careful notice, that the regulations on which all the laws of matter operate are established on a rigidly accurate mathematical basis. Proportions of number and geometrical figures rest at the bottom of the whole. All these considerations, when the mind is thoroughly prepared for them, tend to raise our ideas with respect to the character of physical laws, even though we do not go a single step further in the investigation. But it is impossible for an intelligent mind to stop there. We advance from law to the cause of law, and ask, What is that? Whence have come all these beautiful regulations? Here science leaves us, but only to conclude, from other grounds, that there is a First Cause, to which all others are secondary and ministrative, a primitive Almighty Will, of which these laws are merely the mandates. That great Being, — who shall say where is his Man pauses

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dwelling-place, or what his history! breathless at the contemplation of a subject so much above his finite faculties, and only can wonder and adore!"

GEOLOGICAL HISTORY OF THE EARTH.*

GEOLOGY is the natural history of the earth, as gathered from an examination of its mineral masses. While other sciences are written on paper, this is recorded in the Stone Book, of which the eternal rocks are the leaves. We depend not here upon human testimony; but we delve into the bowels of the earth, and, gathering the bones and relics which have there been sepulchred for ages, we question these and record their wondrous revelations.

Astronomy teaches us, that the materials of our solar system were originally in a fluid or gaseous state. As the sun was in process of formation, from time to time it threw off fragments, which were condensed into planets. Our earth was one of these, and it was thus created, doubtless by an operation which extended through millions of ages.

In its original condition, we suppose the earth to have been a molten mass, and to have gradually hardened as it cooled. While its outer surface thus became solid rock, it is supposed that the interior continued to be in a state of fusion, and remains in that condition to the present day. This curious theory is strongly confirmed by the fact, that as we descend

*For a fuller view of this subject, see "Wonders of Geology."

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